Ballastless railway track structure



Match 1969 KENTARO MATSUBARA ETAL 3, 7

BALLASTLESS RAILWAY TRACK STRUCTURE Filed Nov. 50, 1966 Sheet of e I N VE/V 7026 KENT/1K0 M4 T508442! SEMI 16;, TQHXA M4 A T70 ZNSYS March 1969 KENTARO MATSUBARA ETAL 3,430,357

BALLASTLESS RAILWAY TRACK STRUCTURE Sheet Filed Nov. 30, 1966 N f A 5 5% MW e y m Z M 3 V A 0/ Mi MI M 5 March 1969 KENTARO MATSUBARA ETAL 3, 30,

BALLASTLESS RAILWAY TRACK STRUCTURE Sheet Filed Nov. 30, 1966 ToHyA/vn A rroe/vsys Shet 4 of 6 KENTARO MATSUBARA ETAL BALLASTLESS RAILWAY TRACK STRUCTURE March 4, 1969 Filed Nov. 30, 1966 March 1969 KENTARO MATSUBARA ETAL 3,430,857

BALLASTLESS RAILWAY TRACK STRUCTURE Sheet Filed Nov. 30, 1966 mm l 1w l/EN 7'09 5 A EN 7:420 MA TSUBAQA SE/KI cH/ TOHYAHA Ma 1969 KENTARO MATSUBARA ETAL 3,430,357

BALLASTLESS RAILWAY TRACK STRUCTURE Filed Nov. 30, 1966 Sheet' 6 of e l vvslvmks A s/vnmo m4 505424 5EIK/C/l/ rah MAMA United States Patent 3,430,857 BALLASTLESS RAILWAY TRACK STRUCTURE Kentaro Matsubara, Tokyo, and Seikichi Tohyama, Ohtsuki-shi, Japan, assignors to Japanese National Railways and Kowa Concrete Company Limited, Tokyo, Japan Filed Nov. 30, 1966, Ser. No. 597,948 Claims priority, application Japan, Dec. 27, 1965, 40/ 80,068; July 6, 1966, 41/ 33,972, 41/43,973, 41/43:,974 U.S. Cl. 238-1 4 Claims Int. Cl. E01b 1/00, 21/00, 25/28 ABSTRACT OF THE DISCLOSURE The disclosure relates to an unballasted railway track structure including supports or piers positioned along a roadbed at predetermined intervals longitudinally thereof and spanned by relatively long elongated beams, each beam having its opposite ends supported by a pair of longitudinally adjacent respective supports. Each support has an upper beam-supporting surface formed with projections limiting lateral and longitudinal displacement of a beam supported thereon, and the beams have upper surfaces formed to support and fixedly position the two rails of a track. Resilient shim blocks are interposed between the beam-supporting surface and the undersurface of a beam, and between the projections and end and lateral surfaces of the beam, these shim blocks damping vertical and horizontal impacts on the supported beam. The relative lateral and vertical positions of the rails or track is settable by selecting the thicknesses of the shim blocks.

The disclosure is further directed to a novel method of properly aligning the supports or piers along the road bed.

Background of the invention The conventional track structure composed of ballast and sleepers is liable to rapid development of track irregularities, and therefore requires a great deal of maintenance. This is why a ballastless or unballasted track is preferred. In the New Tokaido Line of Japan, wooden blocks embedded in concrete bed support the rails which are elastically fastened to them. This structure is intended to enable the surfaces of the wooden blocks to be planed by a plane trolley, for surfacing. In laying the track, the track skeleton, complete with wooden blocks, was suspended and then concrete was deposited beneath. But this method does not guarantee the desired accuracy of the work. Moreover, to plane the wooden blocks, it is necessary to cut the long continuous rail sections and remove the fastenings. The work is very troublesome. Actually, rectification of track is not carried out, and the geometrical track irregularities are left as they are to some extent. Another example of ballastless track is the one using wooden sleepers fixed on the stringers of a steel bridge. But the maintenance of this type of track is also troublesome.

Summary of the invention One of the objects of the present invention is to provide a ballastless track structure which is free of the aforementioned defects and is easy to construct with a very high degree of accuracy, and which permits maintenance operations without loosening the fastening but leaving the long continuous rail sections as they are. It is thus applicable to modern railways where high speed trains are to run very frequently. Another object of the present invention is to provide a practical means of adjusting the position of supports when supports are laid in a given alignment at fixed intervals.

Therefore, the present invention provides a new bal- .and laterally by means of respective elastic blocks attached to the supports, so that the track can be adjusted as to the vertical and lateral positions thereof by changing the thickness of the elastic blocks.

This invention will find a wide range of application. On a hard roadbed or a short bridge, the supports are built on firm foundations, or on the piers and, on a deck girder bridge or long span, the supports are built on the main girder. In the case of a truss bridge or the like, the cross beam can be used as the base for the supports. The stringer or slab to which the rail is to be fastened, as well as the supports, are fabricated in a workshop with a very high degree of accuracy in dimensions.

If the supports are laid correctly, the position of the beams or slabs resting on them is automatically fixed correctly, and minute adjustment of 0.5 to 30 mm. can be easily made by controlling the thickness of the blocks placed between the supports and beams or slabs. Hence this structure can be maintained easily and made to conform even more accurately to specifications through maintenance services.

The reinforced concrete or steel supports and stringers or slabs of the invention track structure correspond to the ballast and sleepers of the conventional track. Therefore, there will be few track irregularities. Even when geometrical irregularities occur for some reason or other, this new track structure can easily be corrected by simply changing the thickness of the blocks mentioned above, and its maintenance cost is very low.

In a modern high speed railway laid with long continuous rail sections, the maintenance work involving the removal of rails is painstaking and attended by difiiculty. When maintenance work can be carried out on the track with the long rails retained as they are, which is the case with the present invention, it is a great benefit to railroading.

Brief description of the drawing In the following passages, the application of this invention will be explained in detail referring to the drawings.

FIGS. 1A, 1B and 1C are schematic profiles illustrating the unballasted track structure as arranged, respectively, on a hard road bed or short span bridge, on a long span bridge and on a truss bridge.

FIGS. 2 and 3 are perspective views showing the reinforced concrete support and slab or beam in two examples of application.

FIG. 4 is a transverse cross section of the rail fastenings used in this invention.

FIG. 5A is a partial side elevation view illustrating the supporting structure as arranged on a cross beam of a truss bridge.

FIG. 5B is a sectional view taken on the line YY of FIG. 5A.

FIGS. 6 to 11 are sketches illustrating the method of adjusting the positions of the supporting tablets of this invention.

FIG. 6 is a schema illustrating the visual aligning method.

FIG. 7 is a perspective view of the support equipped with ring stands.

FIGS. 8 and 9 illustrate the visual aligning of the supports.

FIGS. 10 and 11 indicate the positions of visual aligning rings when the supports are arranged as shown 1n FIGS. 8 and 9 respectively.

Description of the preferred embodiments Referring to the drawings, FIGS. 1A, 1B and 1C are profiles showing examples of the arrangement of the supports and stringers or slabs of the track structure of the invention. 1 indicates the support, 2 is the stringer or slab and 3 is the rail. FIG. 1A shows the arrangement in the case of hard roadbed or short span bridge. The support 1 is laid on a firm foundation 4. FIG. 1B shows the arrangement in the case of a comparatively long bridge. The support 1 is laid on the main girder 4' of the bridge. To prevent the longitudinal expansion and contraction forces of the long rail sections from being augmented by the reaction due to the contraction and expansion of girders, the bridge seats of the girders 4 are so arranged that the direction of contraction and expansion of the girders is alternately reversed relative to that of the rails. FIG. 10 shows the arrangement in the case of a truss bridge. The dot-and-dash line indicates the centerline of the truss skeleton. In this case the supports 1 are on the cross beams of the bridge.

In any case, the length of beam or slab 2 is determined from the deflection of track skeleton due to weight and load, and such other factors as economy. But, generally, a length of about 5 meters is economical. At this length, a curved track can use the same structure as a straight or tangent track, by shifting the position of rail several millimeters sidewise by means of the fastening equipment described later. Also, when the beam is of this length, it is easy to transport and the amount of the contraction and expansion of the girder due to temperature change can be limited to about 2 mm.

To prevent the contraction and expansion forces of the beams or slabs due to temperature from augmenting, through fastenings, the longitudinal expansion and contraction forces of the long rail sections, adjoining beams or slabs are bolted together on alternate supports so as to form fixed ends (see FIG. 1), and are not bolted on the intermediate supports so as to form free ends. In this way, the adjoining beams or slabs contract and expand in mutually reverse directions, and their forces are offset mutually cancelled.

It is necessary for the position of the beam or slab 2 to be easily adjusted laterally and vertically on the supports. Diverse means are conceivable to this end. The following are detailed explanations of the preferred embodiments of the present invention.

In FIG. 2, which shows the device to support the slab on which the rail is secured, the slab 2 rests on one end of the support 1 and to clarify the explanation, no slab is shown on the other end. The support 1 is made of precast reinforced concrete. Rising from its top 5, there are side walls 6 on its both sides and these side walls are connected by the center wall 7, the walls 6 and 7 as a whole forming an H-shaped wall. The clearance between the side walls 6 is just wide enough so that these walls engage or are closely adjacent the end of the slab 2 on its both sides. The center wall 7 engages or is closely adjacent ends of two consecutive slabs. The support 1 has four shallow flat notches 8 on its surface 5 located symmetrically. Also, the side walls 6 have four shallow flat notches 9 located symmetrically. These notches 8 and 9 accommodate supporting blocks 10 and 11, respectively, for adjustments in vertical and lateral directions. Also, between the center wall 7 and the two slabs, 4 supporting blocks 12 are inserted to support the slabs lengthwise. These supporting blocks are made of an elastic material which damps the impact Without being much deformed.

As the thickness of these supporting blocks are increased or decreased, the position of the slab 2, that is the position of the rail 3 lying on the slab, can be adjusted The notches 8 and 9 open laterally and upwardly outwardly, respectively, so that the supporting blocks 10 and 11, as well as the supporting blocks 12, can easily be taken out and replaced for the purpose of the correction of position of the rail even after the track is laid.

The slab 2 in this embodiment is made of precast reinforced concrete and is grooved at 13 on its top surface to receive the rail base. It has bolt holes 14 for the fastening of the rail. The slab 2 has thick flanges 15 on both sides at its end. These flanges are a little higher than the aforementioned H-shaped wall, and support the ends of the spring 16 from below. This spring is engaged with the slab 2 by means of a vertical bolt 17 embedded in the H-shaped wall, so as to press the support and the slab together.

At every other support, two longitudinally adjacent slabs are connected by bolts and nuts 19 which extend through horizontal holes 18 bored through the side flanges 15 at the ends of the slabs and through the center wall 7 of the H-shaped wall structure. Thus fixed ends of the slabs are formed. In a stretch where a long rail does not move, the bolt 19 need not be tightened firmly, but may provide some play or clearance. Then, the longitudinal contraction and expansion force of the long rail do not increase even when the girders contract or expand an amount corresponding to the play or clearance just mentioned. In other words, it serves to compensate the contraction and expansion forces of the bridge due to temperature change. Thus, even a section laid with long rails can omit the expansion joint for the track on a bridge when every other support is fixed and some play or clearance is provided, if necessary. The other support is freed and the creep-resistive force of the fastenings is decreased.

Shown in FIG. 3 is another embodiment of precast reinforced concrete support according to the present invention. Like FIG. 2, this also omits the slab extending toward the front side of the drawing, facilitate explanation. In this case, a rectangular projection 20 is positioned on the top plane 5 of the base support 1 in its middle. The end of the slab 2 is rectangularly notched at 21, where about a half of the projection fits in. The slab is thus constrained laterally and longitudinally on the three sides of the notch 21 and the same sides of the projection 20.

The base support 1 has four shallow flat notches 8 arranged symmetrically on its top 5. The projection 20 also has four shallow fiat notches 9 at symmetric positions on the two sides parallel with the axis of the rail. All these notches 8 and 9 accommodate the vertical and lateral positioning blocks 10 and 11, respectively. Also, at the fixed end, between the projection 20 and the notch 21 of slabs, supporting blocks 12 are inserted. These supporting blocks 10, 11 and 12 are made of an elastic material which damps the impact without being much deformed.

As the thickness of these positioning blocks may be increased or decreased, the position of the slab 2, and the position of the rail 3 lying on the slab, can be adjusted. The notches 8 and 9 open laterally and upwardly, respectively, so that the supporting blocks 10 and 11, like the supporting block 12, can easily be taken out and replaced for the purpose of correction of the position of the rail even after the track is constructed or laid.

The slab 2 in this embodiment is also made of precast reinforced concrete and is grooved at 13 to have the rail base rest on it. It has bolt holes 14 for the fastening of the rail. The slab 2 has thick flanges 15 on 'both sides at its ends. The spring 16 is engaged with the slab 2 by means of a vertical bolt 17 embedded in the base support 1, the spring ends bearing on the flanges 15 of the slab so as to press the support and the slab together.

At every other support, two opposing slabs are connected by bolts and nuts 19 which extend through the horizontal holes 18 bored through the side flanges 15 at the ends of the slabs. Thus, the fixed ends of the slabs are formed. The other end of each support is not bolted and forms the free end.

The base support shown in FIGS. 2 and 3 is common for straight and curved track and is manufactured at a workshop. When it is installed, it is suspended at the right position and concrete is deposited or grouted around and beneath it so as to build it into a fixed structure.

FIG. 4 shows an example of a rail fastening device on the ballastless track of this invention. The rail 3 is placed in the middle of each of the grooves 13 provided on the top of the slab 2, with a tie-pad 22 laid between the rail base and the bottom of the groove, and a pair of transverse force sustainers 23 are put between the sides of the rail base and the sides of the groove 13. The transverse force sustainers are preferably made of an insulating and hard material such as fiber reinforced plastic. The sustainers are to rest on the bottom of the groove, and the upper surfaces thereof are formed with a depression 24 to support one end of the spring 25. The spring 25 is a plate spring of an angular cross section, and its other end rests on the upper surface of the rail base. The angle spring 25 bears, along its vertical axis, another plate spring 26 'which has a flattened elliptical shape and is cut open at its bottom. These springs 25 and 26 are penetrated by a bolt 27 which runs through holes at their centers and is embedded in the body of the slab 2. Thus, with the aid of nuts and threads at the tops of these bolts, these springs are biased toward the slab. In this case, an insulating collar 28 is inserted through the holes of the springs, i.e. around the bolt, so as to insulate the rail from the slab. According to this design, the lateral position of the rail is determined by the transverse force sustainers, so the springs 2'5 and 26 receive the vertical force only and are free from the effect of bending forces due to transverse forces from the rail. Moreover, since the spring is double, the rail fastening strength is quite large. The height of rail can be adjusted by employing pads of various thicknesses at 0.5 mm. increments. Further, the track gauge and alignment can be adjusted by changing the width of the transverse force sustaining filler at 0.5 mm. increments. Therefore, it is feasible to reduce the tolerance of precision of the track skeleton to 0.5 mm. Also, in both a plane curve and a vertical curve, the straight beams serve without any diificulty.

It will be understood that the tracks as indicated by FIGS. 2, 3 and '4 are little liable to geometrically irregularities, which would otherwise be caused by operation of trains, and are quite easy to maintain.

Further, both base supports 1 and slab 2 can be manufactured at a workshop and, as such, they can be made accurately, with tolerances of dimensions easily reduced to 1 mm. or less. Therefore this track structure can be laid with great accuracy, if only the supports are laid correctly. To adjust the laying of the supports, it is advantageous to use the method of adjusting the position of supporting tablets, which method will be explained in detail below.

Circular rings for visual aligning are installed at certain positions of the supports, and alignment of the track will be obtained if the line of rings looks like a pipe when viewed from one end. This is a very simple and convenient method. For the plane curve, transition curve and vertical curve, in particular, some rings are set in correct position beforehand by survey, desirably at intervals of 25 or m., and the intermediate stretches will be aligned by adjusting the series of the rings so as to show a pipe-like perspective. Marked 29 in FIGS. 2 and 3 is this circular ring, which can be fixed at a prefixed position of each support 1 by a stand '30 as desired. As the deviation of the visual aligning rings 29 and 29 indicates any twist of the support 1, the position of the support can be corrected through this means also.

The proper height of the visual aligning ring is preferably the rail level. In installing the supports, greater accuracy will be attained if rings along the center line of track are used in addition to those on both sides.

The foregoing examples of the present application refer to the cases where this invention is applied to a hard roadbed. But, as a matter of course, it is applicable to track within a tunnel, and also to the track on a comparatively long bridge, as shown in FIG. 1B, by arranging the supports on the main girder at appropriate intervals.

The application of the structure of this invention may be extended to steel truss bridges, as shown in FIG. 1C. FIG. 5 shows an example of its application where the member marked 31 is the cross beam of a truss bridge. A steel case 33, accommodating an elastic block 32, is bolted to the top of the cross beam. The stringer or beam 2 on which to fasten the rail is made of steel and both its ends are cut to a half or smaller height so as to lap-joint two adjoining beams, with a shoe 34 put in between to hinge them. The lower stringer or beam 2 end has a foot 35 which fits in the supporting case 33 and rests on an elastic block 32. At the spot it is supported, the beam 2 has a projection 36, similar to the underside projection 35, on the side toward the outside of the gauge. This projection fits in a side supporting case 38 which is supported by a bracket 37 on the top of the cross beam 31, and rests on the elastic block 39 accommodated in the case 38. The position of the beam 2 is easily adjusted by changing the thickness of the shim 4t) placed in the case together with the elastic block. In the figure, the shoe 34 and case 33 are fixed. But they may be made movable if it is required. The idea of arrangement of the movable end and fixed end is the same as in the case of the concrete bridge in FIG. 1B. The rail is laid on the channel steel 41 installed on the beam 2 or 2', by the same method as FIG. 4. Needless to say, both stringers of the track in this example must be connected crosswise at appropriate intervals to secure the stability of the gauge.

Generally, it takes a great deal of labor and a long working time to maintain accurately the track laid with bridge sleepers on a bridge, because the wooden sleepers are very liable to deformation and loosening. T o the contrary, the track structure of the invention enables one to maintain it with higher accuracy with less labor and time, so it is very economical.

In the next place, detailed explanation will be given of the second object of this inventionthe method of adjusting the position of such supporting tablets as sleepers (including the base support dealt with in the foregoing passages).

In this method, ring stands are aflixed at the specified positions of each support, and the line of the hollow rings can be viewed like a pipe line parallel to the center line of the track, by such optical instruments as levels or transits if the supports are positioned correctly. As any deviation of a ring stand from the correct position can be immediately detected by visual observation of the correct pipe line, the support can easily be aligned correctly even in the case of plane or vertical curves, as well as in the case of transition curves.

The ring stand afiixed at the specified position of the support holds a visual aligning ring having a cross wire, which enables the amount of deviation of the rings to be easily determined. A pair of these ring stands are installed in such a way as to allow removal and resetting on both sides at the end of the aforesaid base support, by suitable means not liable to cause dislocation during the installation work. In carrying out the work, the supports to which the ring stands have been aflixed are first located correctly at a proper interval on the section proposed, which is preferably 50 to meters in ordinary cases. Then similar supports complete with ring stands are arranged at specified intervals between the correctly laid supports. These visual aligning rings are visually ruled from one side, and the supports whose visual aligning rings are out of line are moved to the correct position.

This method will be further explained by referring to the figures as below.

FIG. 6 schematically shows the idea of the visual aligning method of this invention as to the case where the supports 6-1 are to be arranged straight. As indicated in FIG. 7, each support is equipped with a pair of ring stands (T and T) at specific relative points at one end. The visual aligning rings 62 and 6-2 of these ring stands T and T are supported by the supporting posts 6-3 and 6-3 and bases 6-4 and 64', and the bases 64 and 6-4' are bolted or otherwise properly fixed at the specified positions of the support 6-1. The visual aligning ring 6-2 has a cross wire '6-5 representing the horizontal and vertical lines of the plane perpendicular to the visual ruling line AB.

When installing the supports, as stated already, a number of supports complete with ring stands are lined along the section proposed. Then, the positions of the nearest support 6-1a and the farthest 6-1b are correctly fixed (in the case of straight or tangent track). Next, an optical instrument 66, like a transit or level, is set on the extended part of the line connecting the center of the visual aligning ring 6-1a with that of the other ring 6-11). Ruling by vision will immediately detect the visual aligning rings deviating from the correct line. In this process, the amount of correction in vertical and lateral directions can easily be determined by virtue of the cross wire device.

Thus, as the tablets whose visual aligning rings are out of line are moved to the right position, the alignment can be accurately adjusted without any difficulty. In FIG. 8, the support 6-1c is off the correct line in one direction and the support 61d is off the correct line in two directions. On the support 6-1, the visual aligning rings 62 and 6-2 are installed along the visual ruling line at specific relative positions. Therefore, the supports can be adjusted as to the two directions at the same time by fixing the centers of the two visual aligning rings to the correct line at the same time. As such, this method facilitates the laying of sleepers among other things.

In the case of a straight or tangent section, as indicated by FIG. 8, the visual aligning rings, after being adjusted, present a pipe-like perspective as shown in FIG. 10. In the case of a curve like the one in FIG. 9, they form a curved pipe as shown in FIG. 11. Therefore, even in the case of an arrangement with a curve, the positions of the supports can be corrected easily and accurately, since the visual aligning rings not forming a smoothly bent pipe can be readily detected.

What is claimed:

1. An unballasted railway track structure comprising, in combination, supports positioned along a road bed at predetermined intervals longitudinally thereof; relatively elongated beams spanning said supports longitudinally of the road bed, each beam having its opposite ends supported by a pair of longitudinally adjacent respective supports; each support having an upper beam-supporting surface formed with projections limiting lateral and longitudinal displacement of a beam supported thereon; said beams having upper surfaces formed to support and fixedly position at least one rail of a track; resilient shim blocks interposed between and engaging said beam-supporting surface and the under-surface of a beam, and interposed between and engaging said projections and end and lateral surfaces of the beam, said blocks damping vertical and horizontal impacts on the supported beam; the relative lateral and vertical positions of the rail being settable by selecting the thickness of said shim blocks; said projections including an H-shaped wall standing on the beamsupporting surface of each support; the ends of adjoining beams on which rails are fixed fitting in the clearances of the H-shaped wall; each beam thus being constrained on the support in three directions, vertical, longitudinal and lateral, at the same time.

2. An unballasted railway track structure comprising,

in combination, supports positioned along a road bed at predetermined intervals longitudinally thereof; relatively elongated beams spanning said supports longitudinally of the road bed, each beam having its opposite ends supported by a pair of longitudinally adjacent respective ends supported by a pair of longitudinally adjacent respective supports; each support having an upper beam-supporting surface formed with projections limiting lateral and longitudinal displacement of a beam supported thereon; said beams having upper surfaces formed to support and fixedly position at least one rail of a track; resilient shim blocks interposed between and engaging said beam-supporting surface and the under-surface of a beam, and interposed between and engaging said projections and end and lateral surfaces of the beam, said blocks damping vertical and horizontal impacts on the supported beam; the relative lateral and vertical positions of the rail being settable by selecting the thicknesses of said shim blocks; said projections including a rectangular projection at the center of the beam-supporting surface of each support; a rectangular notch being formed at each end of a pair of adjoining beams on which the rails are fixed; each notch partially embracing said projection; each beam thus being constrained on the support in three directions, vertical, longitudinal and lateral, at the same time.

3. An unballasted railway track structure comprising, in combination, supports positioned along a road bed at predetermined intervals longitudinally thereof; relatively elongated beams spanning said supports longitudinally of the road bed, each beam having its opposite ends supported by a pair of longitudinally adjacent supports; each support having an upper beam-supporting surface formed with projections limiting lateral and longitudinal displacement of a beam supported thereon; said beams having upper surfaces formed to support and fixedly position at least one rail of a track; resilient shim blocks interposed between and engaging said beam-supporting surface and the undersurface of a beam, and interposed between and engaging said projections and end and lateral surfaces of the beam, said blocks damping vertical and horizontal impacts on the supported beam; the relative lateral and vertical positions of the rail being settable by selecting the thicknesses of said shim blocks; the upper surface of each of said beams being formed with at least one substantially rectangular cross section groove extending longitudinally thereof; tie pads extending centrally along each groove, and supporting a rail extending centrally along each groove; transverse force resisting members positioned in each groove on opposite sides of the rail base and engaging the rail base and the respective side edges of the grooves; bolts anchored in the support and extending upwardly through apertures in said members; a first bowed spring associated with each bolt and having a substantially central aperture through which the bolt extends, each first bow spring having one end engaged with the upper surface of a rail base and its other end engaged with the associated member; a second spring operatively associated 'with each bolt and in the form of a flattened ellipse with laterally spaced ends engaged with the associated first bowed spring, each second spring having an aperture through which the associated bolt extends; and nut means threaded on the upper end of the associated bolt for compressing said first and second springs.

4. An unballasted railway track structure, comprising, in combination, supports positioned along a road bed at predetermined intervals longitudinally thereof; relatively elongated beams spanning said supports longitudinally of the road bed, each beam having its opposite ends supported by a pair of longitudinally adjacent respective supports; each support having an upper beam-supporting surface formed with projections limiting lateral and longitudinal displacement of a beam supported thereon; said beams having upper surfaces formed to support and fixedly position at least one rail of track; resilient shim blocks interposed between and engaging said beam-supporting surface and the under-surface of a beam, and interposed between and engaging said projections and end and lateral surfaces of the beam, said blocks damping vertical and horizontal impacts on the supported beam; the relative lateral and vertical positions of the rail being settable by selecting the thicknesses of said shim blocks; and a pair of stands, each having a ring at its top, removably fixed on each support at specific relative positions, the plane of each ring being oriented at a right angle to the direction of the track, whereby the position of supports can be adjusted by sighting through said rings along the direction of the track.

1 0 References Cited UNITED STATES PATENTS 6/1956 Hastings et a1 238-25 1/ 19-67 Moses et al 238-25 US. Cl. X.R. 

